1. Field of the Invention
The present invention relates to an agricultural implement for tilling soil and to a method for row crop farming, and more particularly to a rotary plow or moldboard for producing an elevated row of comminuted soil.
2. Description of the Prior Art
An important requirement in agriculture is the formation in soil of seedbed rows and furrows or hardpan middles in combination with the seedbed rows. In dry land farming, where the natural rainfall is adequate to produce a crop, the crops are farmed in elevated seedbed rows with furrows formed intermediate the rows. In this method of farming, farmers are continually faced with the problem of receiving sufficient rainfall at the right time to derive a profitable yield from their crop. Conservation of the moisture as it is received is of utmost importance. Of equal importance to the dry land farmer is the use of the watershed from surrounding unused land to supply extra moisture to the cultivated field. The soil of the seedbed rows is preferably finely comminuted so that it will absorb large volumes of watershed moisture and retain the moisture during periods of insufficient rainfall for the benefit of the growing crop.
In farming irrigated row crops, it is common practice to form elevated seedbeds which are bounded on laterally opposite sides by parallel irrigation furrows or hardpan middles from which water seeps into the beds. According to conventional practice, the elevated seedbeds must be shaped, prepared for seeding, seeded and cultivated using several different and specialized machines. For example, a bed shaping implement is utilized for forming the furrows in intermediate raised seedbeds, another implement is utilized for leveling the bed surface and tilling the bed in preparation for planting, and still another implement is utilized for planting seeds. This procedure is relatively costly and time consuming.
Various soil working implements have been constructed for producing the elevated seedbeds in furrows necessary for row crop farming. One commonly used tilling implement which is driven by a towing vehicle includes a cylindrical drum or rim mounted for rotation on a shaft which extends laterally with respect to the line of travel of the tilling implement. Soil digging teeth are secured to the drum and are arranged to slice the soil into compact molds from the ground surface and deposit the molds to the rear of the implement in an inverted condition. In such an arrangement, the cutting surfaces of the teeth compact the soil thereby transmitting a shock to the rim and causing the rim to drift away from its line of travel. The shock generated by the compacting action is also transmitted to the power mechanism which rotates the rim possibly causing damage thereto. A related problem to this type of tooth arrangement is the clogging of soil around the rim and along the face of the tooth which interferes with the cutting action. The clogging effect is particularly severe when the soil is wet. Also, when the moisture content of the soil is relatively low, it is difficult for the teeth to cut through as they are compacting the dry soil. Thus the plowing season for conventional rotary plows is greatly restricted to times when the soil is neither too wet nor too dry. Furthermore, the compacting action of the teeth increases the horsepower requirements of the implement.
It is desirable in the tillage of soil for certain row crops that the soil be comminuted or broken up into very small portions so that the soil in the seedbed is relatively light and fluffy and aerated as compared to the unplowed soil. Such soil consistency is important for promoting proper root growth and for sustaining the capillary flow of moisture through the soil to the roots. Conventional tilling apparatus is available for comminuting soil; however, multiple passes with different agricultural implements must be made to form elevated seedbeds of comminuted soil and the adjacent furrows. The conventional implements which are available are typically characterized by lateral drift problems, clogging of the teeth, and uneven resistance to forward rolling movement of the implement as the teeth engage the soil, thereby producing destructive vibration and pulsations which are transmitted to the implement and to the towing vehicle.
In view of the difficulties and disadvantages inherent in conventional soil working implements, it is a particular object of the invention to provide method and apparatus which will comminute, mulch and aerate the soil in elevated seedbeds by means of a self-cleaning rotary plow with relatively less expenditure of horsepower, and which offers minimum resistance to the forward rolling movement of the implement as it engages the soil, thereby avoiding side drift and mechanical pulsation problems.